Melt viscosity modulus

Solution viscosity, melt viscosity, modulus of elasticity... 

Therefore, the main flow properties of plastics in the widest sense are influenced by the mean molar mass. These properties include melt viscosity, modulus of elasticity and shear modulus above the glass transition range, creep behavior, stress cracking behavior, strain at break, mechanical strength, solubility and swelling behavior, etc. 

Material added to a plastic to increase its workability and flexibility. Plasticizers tend to lower the melt viscosity, the glass transition temperature and/or the elastic modulus. 

However, the thermoplastics have the disadvantages of not being stiff due to their low modulus and a lack to flow into detailed molds due to their inherently high melt viscosity. Because of the relatively... 

Above its melting point of 327° C, polytetrafluoroethylene has some properties more like a rubber than a liquid. The instantaneous Young s modulus is 2—3 X 107 dynes/cm2, and the melt viscosity is about 10u poises at 380° C (Nishioka and Watanabe). Because of this very high melt viscosity, it is not feasible to process the polymer by conventional extrusion or injection molding. Instead, techniques similar to those of powder metallurgy are employed. These involve three basic steps. 

The bulk rheological properties of the PFPEs, including the melt viscosity (p), storage modulus (G ), and loss modulus (G"), were measured at several different temperatures via steady shear and dynamic oscillation tests. Note that we denoted p as melt viscosity and r as solution viscosity. An excellent description of the rheology is available in Ferry [99]. 

The significance of such degradation is realized when one considers that any reaction which randomly breaks one carbon—carbon bond per thousand bonds in the polymer would reduce the average molecular weight by one-half (23). This effect would be observable in properties such as melt viscosity, tensile strength, and bulk modulus. 

Plasticizers and flexibilizers are incorporated into an adhesive formulation to provide it with flexibility and/or elongation. Plasticizers may also reduce the melt viscosity of hot melt adhesives or lower the elastic modulus of a solidified adhesive. Similar to diluents, plasticizers are nonvolatile solvents for the base resin, and by being incorporated into the formulation, they separate the polymer chains and enable their deformation to be more easily accomplished. Plasticizers generally affect the viscoelastic properties of the base resin whereas diluents simply reduce the viscosity of the system. Whereas diluents result in brittle, hard adhesive systems, plasticizers result in increased flexibility and lower modulus. The temperature at which polymers exhibit rubbery properties (i.e., the glass transition temperature) can also be modified by incorporating plasticizers. 

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